December 2010 - Boost - lists.preview.boost.org

Boost Users Map
by Dean Michael Berris 21 Dec '10

21 Dec '10

Good day everyone! Thanks to the great idea that some people on the #boost IRC channel in FreeNode proposed, (thanks to heller, mjcaisse, for the prodding and the ideas) I've started a Google Map to show where in the world Boost Users are -- please feel free to add yourself and your location and maybe connect with other Boost Users in your area! You can add yourself to the map from here: http://goo.gl/RbmNq -- it might require that you log in using your Google account for you to add your location to the list. Please add yourself to the map and be counted -- show how well Boost is used around the world! Thanks in advance and I definitely look forward to seeing users of Boost around the world at least in the map! -- Dean Michael Berris about.me/deanberris

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Interest in a list comprehension library?
by Brent Spillner 21 Dec '10

21 Dec '10

I uploaded sample code to the Vault (in the "Miscellaneous/" directory) that provides a concise notation for list comprehensions. The comprehensions are evaluated lazily and can be used to populate a std::list, vector, or deque, appended to the same, inserted after a given iterator, or interpreted as a boost::range, including compatibility with BOOST_FOREACH. Containers, iterator-defined ranges, or nullary function objects can be used as generators, and arbitrary function objects can be used to specify filter conditions. For example, the Pythagorean Triples example from http://rosettacode.org/wiki/List_comprehensions can be coded as std::vector< boost::tuple<int,int,int> > triples =_(x, y, z)[x <<= range(1, n), y <<= range(x, n), z <<= range(y, n), x*x + y*y == z*z]; , and the (toy) prime number generator at http://www.secnetix.de/olli/Python/list_comprehensions.hawk can be implemented as std::vector<int> nonprimes = _(j)[i <<= range(2, sqrt_max), j <<= range(2 * i, sqrt_max * sqrt_max, i)]; boost::function<std::vector<int>::const_iterator ()> is_composite = bind(std::find<std::vector<int>::const_iterator, int>, nonprimes.begin(), nonprimes.end(), ref(p)); BOOST_FOREACH(int x, (_(p)[p <<= range(2, sqrt_max * sqrt_max), call(is_composite) == nonprimes.end()])) { std::cout << x << std::endl; } (Note the use of call() to represent delayed invocation, and the extra () around the comprehension when used with BOOST_FOREACH.) I've tested this so far with GCC 4.4.4, GCC 4.5.2, and Clang 2.9, using Boost 1.42 and 1.45, and with and without -std=c++0x. Reports of success/failure with other environments are most welcome. The code is still in a prototype stage, so I'm more than happy to take design suggestions and would love to hear about use cases I've overlooked. If there's sufficient interest I will work on getting it to production quality and writing some real documentation. I apologize in advance for wasting everybody's time if something like this already exists in Phoenix; I'm not too familiar with it but I skimmed the docs and didn't see anything. Enjoy, Brent

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Interval Trees & ICL
by Bruce Adams 20 Dec '10

20 Dec '10

Hi, I have been working on a problem for which a suitable solution is an efficient container of intervals. The two main candidates would be something like to boost::split_interval_set or a centred interval tree (along the lines of http://en.wikipedia.org/wiki/Interval_tree) It seems to me that the characteristics of an interval tree differ sufficiently from the containers defined in ICL that they might make a useful addition. For the case where there is a potentially large number of overlapping intervals a split_interval_set will be less efficient than an interval tree. In the worst case intervals would be split down to unit size. Searching the archives I see there was some discussion of interval trees in the context of ICL but the additional of an interval tree container did not, as far as I can tell, come up (perhaps because it should first appear in a boost release before there is any consideration of adding to it?). I have a few questions: 1. Is there a specific name for the data structures provided by the ICL? I have searched the literature and cannot find any mention of sets that split or combine intervals this way. It is either a genuinely novel concept, which I find difficult to believe, or I haven't used the correct search terms (interval, extent or segment). Either way, I would like to update wikipedia appropriately to help other lost souls. 2. Are there any compelling reasons why interval trees are less useful than the containers provided by the ICL? 3. Perhaps based on the answer to 2. Would interval trees be a sensible addition to the ICL? 4. Are there any other classes of interval container worthy of mention? Regards, Bruce.

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1.46 closing for new libraries tomorrow
by Vladimir Prus 20 Dec '10

20 Dec '10

Our calendar at http://www.boost.org/development/index.html say that 1.46 will be closed for new libraries tomorrow. I believe we have two libraries that were accepted, but not released. On those, Interval Containers library appears to have been merged to release branch already. The other one, Ratio, does not appear to be present in trunk, and therefore is not likely to be included in 1.46. The next deadline is on Jan 10, when the trunk will be closed for major changes. Thanks, Volodya -- Vladimir Prus http://vladimir_prus.blogspot.com Boost.Build: http://boost.org/boost-build2

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how to distinguish between const char* and const char[N]
by Jochen Wilhelmy 20 Dec '10

20 Dec '10

Hi! is there a (possibly boost powered) way of distinguishing between const char* and const char[N]? e.g. const char* foo = "foo"; bar(foo); bar("foo"); The second call to bar should extract the length at compile time, e.g. template <size_t length> void bar(const char (&data)[length]) {...} The problem is that in the presence of the first variant (void bar(const char*)) the second variant does not get called. -Jochen

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[quickbook] error with links when building documentation
by Christian Henning 19 Dec '10

19 Dec '10

Hi there, I keep getting these strange errors when building my documentation: Error: no ID for constraint linkend: _Tutorial_. Error: no ID for constraint linkend: _extenting_io_. Error: no ID for constraint linkend: _Supported_Formats_. Error: no ID for constraint linkend: _Supported_Formats_. The file I'm trying to build is here: http://gil-contributions.googlecode.com/svn/trunk/gil_2/libs/gil/io_new/doc… plus the jam file http://gil-contributions.googlecode.com/svn/trunk/gil_2/libs/gil/io_new/doc… I read somewhere that I need to use two-pass processing but I don't understand what means. Any help is very welcome. Thanks, Christian

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[quickbook] list rendering
by Cromwell Enage 19 Dec '10

19 Dec '10

Hi, all! I notice that Quickbook converts paragraph-level lists into <programlist> elements in Docbook rather than the <itemizedlist> and <orderedlist> elements that I was expecting. This causes my text to be rendered a bit like code--preformatted with some syntax highlighting. Also, Quickbook list markup nested within table entries are treated as ordinary text. I know I could escape Boostbook markup instead, but my lists contain Quickbook links that I would rather not figure out how to hand-code. Otherwise, thanks for a great documentation tool! Cromwell D. Enage

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Boost.Locale (was Re: [SQL-Connectivity] Is Boost interested in CppDB?)
by Dean Michael Berris 19 Dec '10

19 Dec '10

On Tue, Dec 14, 2010 at 10:48 PM, Edward Diener <eldiener(a)tropicsoft.com> wrote: > On 12/14/2010 9:03 AM, Artyom wrote: >> >> Accidentally (or not) there is a Boost.Locale library that I had submitted >> for a >> formal >> review is stuck in queue waiting for the formal review. >> >> It supports charset conversions and much more of Unicode handling. >> >> And accidentally (or not) it recommends using UTF-8 anywhere >> and not to use wide strings... > > That's fine as long as you realize that it may not be the most common usage > of Unicode for everybody ( such as in Windows programming ). > +1 -- if there was a library that did easy conversion from std::wstring (usually the default in Windows now) to proper UTF-8 encoded std::string in Boost that would be *awesome*. I can totally use that library in cpp-netlib too. ;) I'm not sure, but maybe Spirit.Karma can handle something like that? I haven't checked yet but a string conversion/encoding utility like that would be very much appreciated IMO. > I am looking forward to the review of Boost.Locale. +1 -- Dean Michael Berris deanberris.com

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Trusting Subversion, reducing server load
by Jim Bell 18 Dec '10

18 Dec '10

Doing an SVN update instead of a full check-out would reduce server bandwidth considerably (and reduce test cycle time). I wonder if Ticket #4916 <https://svn.boost.org/trac/boost/ticket/4916> has something to do with the decision (not) to trust Subversion. '--force-update' doesn't wipe out intermediate files as regression.py clearly intends it, making it act like '--incremental'. I think someone should fix #4916, make '--force-update' the default, and see what that does to server load. Then, bring back source browsing if we can.

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[Bug Sprint] The Boost bug sprint has begun!
by Marshall Clow 18 Dec '10

18 Dec '10

As of 7 AM PDT, there are 939 open bugs. [ I see that Vicente and Mattias have already started - that's great! ] General information about the bug sprint is here: https://svn.boost.org/trac/boost/wiki/BugSprintNov2010 General information about how the Trac system works is here: https://svn.boost.org/trac/boost/wiki/TicketWorkflow If you're looking for some way to contribute, I would suggest looking at the oldest active tickets, <https://svn.boost.org/trac/boost/report/1?sort=created&asc=1&page=1> and see if they are still valid. There are about 90 active tickets from 2005-2007. [ Many of them are feature requests, but there are bugs there too. ] Here are a couple of summary tables to give you an idea of where we are: https://svn.boost.org/trac/boost/report/20 Type Tickets Bugs 549 Feature Requests 250 Patches 99 Tasks 28 Support Requests 13 https://svn.boost.org/trac/boost/report/21 Milestone Tickets To Be Determined 352 Boost 1.43.0 102 Boost 1.44.0 98 Boost 1.42.0 75 Boost 1.36.0 50 Boost 1.40.0 48 Boost 1.39.0 44 <blank> 41 Boost 1.41.0 40 Boost 1.38.0 30 Boost 1.37.0 25 Boost-1.45.0 15 Boost-1.46.0 11 Website 1.X 4 Boost-1.47.0 1 Boost.Jam 3.1.18 1 Boost.Jam 4.0.0 1 https://svn.boost.org/trac/boost/report/19 Component Tickets date_time 61 thread 50 Python 48 filesystem 42 build 40 asio 38 mpl 38 smart_ptr 37 Useful reports: https://svn.boost.org/trac/boost/report/1 -- full list of tickets https://svn.boost.org/trac/boost/report/18 -- ticket counts by owner https://svn.boost.org/trac/boost/report/19 -- ticket counts by component https://svn.boost.org/trac/boost/report/20 -- ticket counts by ticket type https://svn.boost.org/trac/boost/report/21 -- ticket counts by milestone -- Marshall

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